skip DoJSON test on plan9

plugins/plugins_test.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"net/http"
 	"net/http/httptest"
+	"runtime"
 	"testing"
 )
 
@@ -33,6 +34,7 @@ type testResp struct {
 }
 
 func TestHTTPRequestDoJSON(t *testing.T) {
+	if runtime.GOOS != "plan9" {
 		ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			_, err := fmt.Fprintln(w, `{"test":"success"}`)
 			if err != nil {
@@ -57,3 +59,4 @@ func TestHTTPRequestDoJSON(t *testing.T) {
 			t.Errorf("Expected 'test'; got '%s'\n", tr.Name)
 		}
 	}
+}